Steam v. Water

[IsabelMurillo3K]

Hey guys!
One of the objectives on outline 3 says:
-Explain why steam at 100 C causes a worse burn than boiling water at 100 C.
I was wondering if someone could answer this objective. I know it has to do with the water changing states, but I am not sure if the release of heat is because of the state transition.
Thank you!

[Joanna Huang]

When steam touches the skin and cools down, it must go through 2 processes: it must go through a phase change from gas to liquid, which requires a lot of energy (aka a lot of heat), and it must also cool down further to the temperature of the skin (releasing even more heat). Meanwhile, the boiling water does not have to go through a phase change, and it only needs to release enough heat to cool down to the temp of the skin. This is why steam causes a worser burn, since it releases more energy.

[Simrah_Ahmed1J]

Its easier to understand using the heating curve of water, I attached my notes about it in a picture.

[Adrienne Chan 1G]

For steam, there's a heat of vaporization that we have to factor in, beyond the actual energy due to heating. They may both be at the same temperature but the steam will have much more energy.

[Kiara Phillips 3L]

I believe it is because when steam is 100 C its about to become air and that moisture mixes with your skin and absorbs faster at the same time that it goes down a phase change when it becomes water when it comes into contact with your skin. Whereas water at 100 degrees C is not at that level yet so when it comes into contact with your skin it is already on the decent down from 100C. Basically because the particles of a gas are at that point increasing in temperature towards evaporation they stick to your skin differently than water particles do producing that extra "burn"